JP2013100792A - Cogeneration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cogeneration device adapted to reliably start a self-sustained operation by appropriately controlling the behavior of an internal combustion engine, when a commercial electric power system fails.SOLUTION: The cogeneration device includes at least a power generation unit comprising a generator connectable to a feed line from a commercial electric power system to an electric load and an internal combustion engine for driving the generator. It is determined whether or not the commercial electric power system fails (S24); and when failure of the commercial electric power system is determined, the internal combustion engine is temporarily stopped (S36); subsequently, when a self-sustaining operation is started, a boosting power supply (DC/DC converter) is connected to a battery 23 to start the internal combustion engine (S38, S40). After the internal combustion engine is started, AC power supply from the generator to the electric load is started (S44).

Description

  The present invention relates to a cogeneration apparatus, and more specifically to a cogeneration apparatus including a power generation unit including a generator and an internal combustion engine that drives the generator.

  In recent years, a power generation unit composed of a generator driven by an internal combustion engine is connected to an AC power supply path from a commercial power system to an electrical load to supply power to the electrical load in conjunction with the commercial power system. A so-called cogeneration apparatus has been proposed in which hot water generated using exhaust heat from an engine is supplied to a heat load (see, for example, Patent Document 1).

  By the way, when a power failure occurs in the commercial power system, a self-sustaining operation is started in which the cogeneration apparatus functions as an emergency power source. In the technique described in Patent Document 1, when a power failure occurs, the electrical connection between the generator and the commercial power system is interrupted, while the generator and the output terminal for independent operation are connected, and the output terminal is connected to the output terminal. It is configured to perform independent operation by supplying electric power.

JP 2006-121888 A (paragraphs 0022, 0027, etc.)

  As described above, when a commercial power system power failure is detected and the operation shifts to the self-sustained operation, it is desirable that operations such as stop and start of the internal combustion engine are also performed in association with each other in order to reliably start the self-sustained operation. However, the technique described in Patent Document 1 has not been disclosed at all in that respect.

  Accordingly, an object of the present invention is to provide a cogeneration apparatus that solves the above-described problems and that appropriately controls the operation of the internal combustion engine to reliably start a self-sustained operation when the commercial power system fails. is there.

  In order to solve the above-mentioned problem, in claim 1, a power generation unit comprising a generator connectable to a power supply path of AC power from a commercial power system to an electric load and an internal combustion engine that drives the generator In the cogeneration apparatus comprising at least a power failure determination means for determining whether or not the commercial power system has failed, and when it is determined that the commercial power system has failed, the internal combustion engine is temporarily stopped and then operated independently. Is started, the internal combustion engine starting means for connecting the boosting power source to the battery to start the internal combustion engine, and after the internal combustion engine is started, supply of AC power from the generator to the electric load is started. Power supply start means.

  In the cogeneration apparatus according to claim 2, comprising an inverter output abnormality determining means for determining whether an abnormality has occurred in the output of the inverter based on an output frequency of the inverter connected to the generator, The power failure determination means is configured to determine that the commercial power system has failed when the voltage of the commercial power system is not more than a predetermined value and it is determined that an abnormality has occurred in the output of the inverter.

  In the cogeneration apparatus according to claim 3, the inverter output abnormality determining means varies the output frequency of the inverter and, when the fluctuation range of the output frequency is equal to or larger than a predetermined value, abnormally outputs the inverter. It was constituted so that it might be judged that this occurred.

  In the cogeneration apparatus according to a fourth aspect, the internal combustion engine starting means is configured to temporarily stop the internal combustion engine when a predetermined time has elapsed since it was determined that the commercial power system was out of power.

  In the cogeneration apparatus according to claim 5, the power supply start means starts supplying AC power from the generator to the electric load after the internal combustion engine is started and the warm-up operation is finished. It was configured as follows.

  In the cogeneration apparatus according to claim 1, it is determined whether or not the commercial power system has a power failure. When it is determined that the commercial power system has a power failure, the internal combustion engine is temporarily stopped and then the independent operation is started. The power supply is connected to the battery to start the internal combustion engine, and after the internal combustion engine is started, the supply of AC power from the generator to the electric load is started. When this occurs, the operation of the internal combustion engine can be appropriately controlled with a simple configuration, and the independent operation can be started reliably.

  In the cogeneration apparatus according to claim 2, it is determined whether or not an abnormality has occurred in the output of the inverter based on the output frequency of the inverter connected to the generator, and the power failure determination means is a voltage of the commercial power system. Is determined to be less than a predetermined value, and when it is determined that an abnormality has occurred in the inverter output, it is determined that the commercial power system has failed, that is, a power failure has occurred based on the voltage of the commercial power system and the output of the inverter. In addition to the effects described above, it is possible to reliably and accurately detect the occurrence of a power failure in the commercial power system.

  In the cogeneration apparatus according to claim 3, the inverter output abnormality determination means determines that an abnormality has occurred in the output of the inverter when the output frequency of the inverter fluctuates and the fluctuation range of the output frequency is equal to or greater than a predetermined value. In addition to the effects described above, it is possible to accurately determine whether there is an abnormality in the output of the inverter with a simple configuration, and thereby more reliably detect a power failure in the commercial power system.

  Specifically, when the output of the inverter connected to the generator is connected to the commercial power system and supplied to the electric load, even if the output frequency is intentionally slightly changed, the fluctuation range is Since the influence of the electric power from the commercial power system is large, it will be suppressed below the predetermined value. On the other hand, if the output frequency of the inverter is changed when the commercial power system fails, the fluctuation range becomes greater than or equal to the predetermined value because the commercial power system is not affected by the power. By utilizing this, it is possible to accurately determine whether or not an abnormality has occurred in the output of the inverter while having a simple configuration, and in order to determine whether or not a power failure has occurred in the commercial power system based on that, It is possible to detect a power outage more reliably.

  In the cogeneration apparatus according to the fourth aspect, the internal combustion engine starting means is configured to temporarily stop the internal combustion engine when a predetermined time has elapsed since it was determined that the commercial power system was out of power. In addition to the effects, the operation of the internal combustion engine can be more appropriately controlled according to the state of the commercial power system, and thus the independent operation can be started more reliably.

  In the cogeneration apparatus according to claim 5, the power supply start means is configured to start supplying AC power from the generator to the electric load after the internal combustion engine is started and the warm-up operation is finished. Therefore, in addition to the above effects, a stable output can be supplied to the electric load from the generator driven by the internal combustion engine.

It is a schematic diagram which shows typically the cogeneration apparatus which concerns on the Example of this invention. It is a block diagram which shows typically the connection relation of the generator shown in FIG. 1, a power generation control part, etc. It is a flowchart which shows operation | movement of ECU of the electric power generation control part shown in FIG. FIG. 4 is a flowchart showing processing performed in parallel with the processing of the flowchart of FIG. 3. FIG. FIG. 5 is a flow chart similar to FIG. 4 showing processing performed in parallel with the processing of the flow chart of FIG. 3. It is a time chart explaining a part of process of the flow chart of FIG. It is a graph which shows the fuel adjustment map of the internal combustion engine shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for implementing a cogeneration apparatus according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic view schematically showing a cogeneration apparatus according to an embodiment of the present invention.

  In FIG. 1, the code | symbol 10 shows a cogeneration apparatus. The cogeneration apparatus 10 is a generator composed of a multipolar coil that can be connected to a power supply path (power line) 16 of AC power from a commercial power source (commercial power system) 12 to an electrical load (for example, a home lighting device) 14. (Shown as “GEN” in FIG. 1) 20, an internal combustion engine (shown as “ENG” in FIG. 1, hereinafter referred to as “engine”) 22, a battery (shown as “Batt”) 23, and power generation control A power generation unit 26 including a unit 24 and an exhaust heat exchanger 30 connected to the engine 22 and causing the cooling water of the engine 22 to exchange heat with exhaust heat to raise the temperature.

  The commercial power supply 12 outputs AC power of 50 Hz (or 60 Hz) at 100/200 V AC from a single-phase three-wire. The power generation unit 26 is integrated and accommodated in the power generation unit case (housing) 32 together with the exhaust heat exchanger 30. Specifically, the power generation unit case 32 is divided into two chambers by a partition 32a. In the figure, the generator 20 and the engine 22 are arranged vertically in the lower chamber 32b, and the exhaust heat exchanger 30 is also arranged. On the other hand, the power generation control unit 24 and the muffler 34 of the engine 22 are accommodated in the upper chamber 32c. That is, the power generation control unit 24 is isolated from the engine 22 and is housed in a separate room from the engine 22 so that heat dissipation from the engine 22 is blocked as much as possible.

  The engine 22 is a water-cooled four-cycle single-cylinder OHV type spark ignition engine that uses city gas (or LP gas; hereinafter simply referred to as “gas”) as a fuel, and has a displacement of, for example, 163 cc. Although illustration is omitted, in the power generation unit case 32, the cylinder head and the cylinder block of the engine 22 are arranged in the horizontal (horizontal) direction, and one piston is arranged in the inside thereof so as to be able to reciprocate.

  The supplied intake air and gas are mixed by a mixer, and the generated air-fuel mixture flows into the combustion chamber and burns when ignited by a spark plug (not shown) to drive the piston. Rotate the crankshaft connected to the piston in the direction of gravity). The exhaust thus generated passes through the exhaust heat exchanger 30, the exhaust pipe 22a, and the muffler 34, and is discharged out of the power generation unit case 32 (outside the warehouse).

  The generator 20 is fixed on a crankcase inside a flywheel (not shown) attached to the upper end of the crankshaft, and generates AC power when rotating relative to the flywheel. Proportional to engine speed. The output of the generator 20 is sent to the power generation control unit 24.

  FIG. 2 is a block diagram schematically showing a connection relationship between the generator 20 and the power generation control unit 24 shown in FIG.

  As shown in FIG. 2, the power generation control unit 24 includes an electronic control unit (Electronic Control Unit; hereinafter referred to as “ECU”) 24a composed of a microcomputer, and a DC / DC converter (step-up power supply; indicated as “DC / DC”) 24b. And an inverter (shown as “INV”) 24c.

  The inverter 24c converts the output of the generator 20 into AC100 / 200V (single phase) via the DC / DC converter 24b. Further, the battery 23 is connected to the DC / DC converter 24b, and when the autonomous operation is started as will be described later, the output of the battery 23 is boosted. Note that the power generation output (rated output) of the power generation unit 26 during normal operation (specifically, when the commercial power supply 12 is not interrupted) is about 1.2 kW.

  The output of the inverter 24 c is supplied to the switchboard 40 via the inverter output relay 36, and is sent from there to the electric load 14 via the power supply path 16 while being connected to the commercial power supply 12. The inverter output relay 36 is controlled to be turned on / off by the ECU 24a of the power generation control unit 24, and is turned on during normal operation. The output of the inverter 24c is also input to the ECU 24a, and the ECU 24a detects the output frequency of the inverter 24c.

  The switchboard 40 is inserted in a power supply path 16 that connects the commercial power supply 12 and the electric load 14. The distribution board 40 includes a main breaker 40a, an ATS (Automatic Transfer Switch) 40b, and an electric load switch 40c in this order from the commercial power supply 12 side. The power line extending from the inverter 24c is connected at a connection point 40d between the ATS 40b and the switch 40c, and a breaker 40e for a cogeneration device is inserted in the middle of the power line.

  The main breaker 40a and the breaker 40e for the cogeneration apparatus are turned off when an overcurrent flows to prevent energization of the overcurrent. The switch 40c for the electric load is turned off when the engine 22 is stopped due to a power failure of the commercial power source 12 as described later, or when the engine 22 in the independent operation is in an idle operation, for example. Is turned on during normal operation and after the power generation output of the generator 20 is stabilized during independent operation).

  The ATS 40b includes an ATS contact 40b1 and an ATS controller (not shown) that controls the operation of the ATS contact 40b1. While the ATS control unit turns on the ATS contact 40b1 during normal operation, and detects a decrease in the ATS primary voltage (that is, the voltage of the commercial power supply 12), the ATS control unit turns off the contact 40b1 to turn off the commercial power supply 12 and the power generation control unit 24. The connection with the inverter 24c is cut off. This prevents power supply (reverse power flow) from the inverter 24c to the commercial power system 12. Further, the ATS controller outputs an “ATS contact ON signal” to the ECU 24a when the ATS contact 40b1 is ON, and when a specified time (for example, 5 seconds) elapses after the contact 40b1 is turned OFF. .

  The switchboard 40 includes a voltage sensor 40f that detects the voltage between the main breaker 40a and the ATS 40b, in other words, the voltage of the commercial power supply 12, and outputs a signal indicating the detected voltage. Further, in the middle of the power supply path 16, more precisely, a current sensor 42 is disposed between the switchboard 40 and the electric load 14 in the power supply path 16, and a current flowing therethrough (in other words, power demand in the electric load 14). A signal indicating is output. The outputs of the sensors 40f and 42 described above are input to the ECU 24a of the power generation control unit 24.

  Returning to the description of FIG. 1, when the generator 20 is energized from the commercial power supply 12 via the inverter 24 c or energized from the battery 23 via the DC / DC converter 24 b, the starter that cranks the engine 22. It also functions as a motor. The ECU 24a of the power generation control unit 24 switches the function of the generator 20 between the starter and the generator and controls the operation of the engine 22 and the like.

  A circulation path 50 through which cooling water (antifreeze) is circulated is connected to the engine 22 and the exhaust heat exchanger 30. The circulation path 50 is formed so as to pass through a heat generating portion such as a cylinder block of the engine 22 and the exhaust heat exchanger 30. Therefore, the cooling water flowing inside the circulation path 50 heats up with the heat generating part to raise the temperature while cooling the engine 22, and also passes through the exhaust heat exchanger 30 to exchange heat with the exhaust of the engine 22. The temperature is raised.

  An electric heater 52 is attached to the downstream side of the cooling water outlet 22 b of the engine 22 in the circulation path 50. The electric heater 52 is energized when, for example, surplus power is generated in the power generation unit 26 and raises the temperature of the cooling water flowing through the circulation path 50. In this specification, “upstream” and “downstream” mean upstream and downstream in the flow direction of liquid (fluid) flowing therethrough.

  The cogeneration apparatus 10 includes a hot water storage tank unit 58 in addition to the power generation unit 26.

  The hot water storage tank unit 58 includes a hot water storage tank 60 and a hot water storage tank unit controller 62. The hot water storage tank unit 58 is accommodated in the hot water storage tank unit case 64. The hot water storage tank unit case 64 is partitioned into four chambers by partitions 64a, 64b, and 64c. The hot water storage tank 60 is housed in a central hot water storage tank chamber 64d in FIG. 1 with its surroundings covered with a heat insulating (heat insulating) material 60a, and stores hot water therein.

  The hot water storage tank 60 and the power generation unit 26 are connected by the cooling water circulation path 50 described above. That is, the circulation path 50 extends from the engine 22 toward the hot water storage tank unit 58, and locally approaches the hot water storage tank side circulation path 60b to form the exhaust heat exchanger 60c. The cooling water flowing through the circulation path 50 in the exhaust heat exchanger 60c transmits heat to the hot water (circulation water) flowing through the hot water tank side circulation path 60b to cool it.

  The water in the hot water storage tank side circulation path 60b, which has been heated by heat exchange in the exhaust heat exchanger 60c and becomes hot water, enters and exits the hot water storage tank 60 and flows so as to circulate between the hot water storage tanks 60.

  The hot water storage tank 60 is provided with an outflow passage 60d. The outflow path 60d is connected to a heat load 66 such as a kitchen or bath hot water supply facility (not shown). A water supply path 60e from the water supply is connected to the outflow path 60d via a mixing valve 68 so that the water temperature can be adjusted.

  An auxiliary boiler 70 is provided in the middle of the outflow path 60d. The auxiliary boiler 70 is connected to a gas supply source, and when a drive signal is output from the hot water control unit 62, the auxiliary boiler 70 burns the gas from the gas supply source and raises the temperature of the hot water flowing through the outflow path 60d.

  The outflow path 60d is connected to a bypass path 60f that bypasses the auxiliary boiler 70 and a branch outflow path 60g that is branched upstream of the bypass path 60f. The bypass channel 60f and the branch flow channel 60g approach locally to form an exhaust heat exchanger 60h.

  The downstream side of the branch outlet 60g is connected to a thermal load 72 such as a floor heating facility in the home, for example, and the thermal load 72 is connected to the hot water storage tank 60 via a reflux path 60i. Therefore, the hot water flowing through the branch outlet 60g is exchanged with the cold air in each room by the heat load 72, and then returns to the hot water storage tank 60 through the reflux path 60i. A water supply pipe 60e is connected to the hot water storage tank 60, and water is supplied (supplemented) when the amount of water in the hot water storage tank 60 decreases.

  Thus, in the cogeneration apparatus 10 according to this embodiment, each room is heated with the hot water supplied from the hot water storage tank 60.

  A hot water storage tank unit control unit (hereinafter referred to as “hot water storage control unit”) 62 is accommodated in an isolation chamber 64e that is partitioned and separated by a partition 64a. Similarly to the ECU 24a of the power generation control unit 24, the hot water storage control unit 62 also includes an ECU (electronic control unit) made of a microcomputer, and is connected to the ECU 24a so as to be communicable.

  In FIG. 1, T is a temperature sensor, V is a valve, P is a pump, and signal lines are not shown, but they are electrically connected to the hot water storage control unit 62. The hot water storage control unit 62 controls the operation of the valve V and the pump P based on the output of the temperature sensor T to control the hot water in and out of the hot water storage tank 60 described above.

  Specifically, the hot water storage control unit 62 drives the exhaust heat pump 74 to pump the cooling water flowing through the circulation path 50 to the exhaust heat exchanger 60c, and exchanges heat with the circulating water flowing through the hot water tank side circulation path 60b. Let

  The circulating water flowing through the hot water tank side circulation path 60b is circulated by the circulation pump 76, and heated by heat exchange with the cooling water flowing through the circulation path 50, and the temperature detected by the temperature sensor 78 is a predetermined temperature (for example, 70). When the temperature reaches (° C.), the hot water storage control unit 62 opens and closes the temperature adjustment valve 80 and supplies the hot water storage tank 60 from above. From the lower part of the hot water storage tank 60, the water whose temperature has been lowered is discharged to the hot water storage tank side circulation path 60b, so that the hot water in the hot water storage tank 60 is maintained at a predetermined temperature.

  The hot water storage control unit 62 adjusts the temperature of the hot water supplied to the heat load 66 by opening and closing the mixing valve 68 and the on-off valve 84 based on the output of the temperature sensor 82 that detects the hot water supply temperature to the heat load 66.

  Similarly, the hot water storage control unit 62 opens and closes the open / close valve 90 of the branch outlet 60g and the open / close valve 92 of the reflux passage 60i based on the output of the temperature sensor 86 that detects the hot water supply temperature to the heat load 72, and also the heating pump The operation of 94 is controlled to adjust the temperature of the hot water supplied to the heat load 72. Furthermore, when the temperature of the hot water supplied to the heat load 72 is low, for example, the hot water storage control unit 62 operates the water path switching valve 96 and the auxiliary boiler pump 98 to supply the hot water heated by the auxiliary boiler 70 to the bypass path 60f. The hot water in the branch outlet 60g is heated using the exhaust heat exchanger 60h and supplied to the heat load 72.

  Based on the above, the operation of the cogeneration apparatus according to this embodiment, specifically, the operation when the commercial power supply 12 is interrupted and then restored will be described.

  FIG. 3 is a flowchart showing the operation of the ECU 24 a of the power generation control unit 24. The illustrated program is executed when the cogeneration apparatus 10 is activated.

  In the following, first, in S (step) 10, it is determined whether or not the result of self-diagnosis performed by a program (not shown) when the apparatus 10 is started is normal. When the result in S10 is negative, there is a possibility that some failure has occurred in the cogeneration apparatus 10, so this program is terminated without executing the subsequent processing, and a failure determination flowchart (not shown) is used. move on.

  When the result in S10 is affirmative, the program proceeds to S12, in which it is determined whether or not the commercial power supply 12 has failed, that is, whether or not the commercial power supply 12 has been detected (detected).

  FIG. 4 is a flowchart showing a process for detecting the power failure. The program of FIG. 4 is performed in parallel with the processing of the flow chart of FIG.

  Referring to FIG. 4, in S100, it is determined whether or not the cogeneration apparatus 10 is in an independent operation (in other words, in a state in which an interconnection operation with the commercial power supply 12 is not performed due to the occurrence of a power failure). Specifically, in S100, it is determined whether or not an abnormality has occurred in the output of the inverter 24c based on the output frequency of the inverter 24c, and when it is determined that an abnormality has occurred, it is determined that the single operation is being performed.

  More specifically, when the output of the inverter 24c is connected to the commercial power supply 12 and supplied to the electric load 14, even if the output frequency is intentionally slightly varied, the fluctuation range is the power from the commercial power supply 12. Since the influence of is large, it will be suppressed below the default value. On the other hand, if the output frequency of the inverter 24c is changed when the commercial power supply 12 is interrupted, the fluctuation range becomes equal to or greater than the predetermined value because the commercial power supply 12 is not affected. In S100, this is used. That is, in S100, the output frequency of the inverter 24c is slightly changed, and when the fluctuation range of the frequency of the output of the inverter 24c that is input (detected) is equal to or larger than a predetermined value, the inverter 24c is caused by a power failure. Therefore, it is determined that the cogeneration apparatus 10 is operating alone.

  When the result in S100 is negative, the subsequent processing is skipped. When the result is affirmative, the process proceeds to S102, and the inverter output relay 36 is turned off.

  Next, the process proceeds to S104, and based on the output of the voltage sensor 40f, is the state of the voltage of the commercial power supply 12 between UN or VN maintained for a first predetermined time (for example, 100 msec) or longer for a first predetermined time (for example, 36 V) or less? Judge whether or not.

  When the result in S104 is affirmative, the routine proceeds to S106, where it is determined whether or not the state in which the ATS contact-off signal is output from the ATS 40b continues for a second predetermined time (for example, 500 msec), that is, the voltage drop of the commercial power supply 12 is detected. It is also detected on the side, and it is determined whether or not the state continues for a second predetermined time. When the result in S106 or S104 is negative, the process returns to S104, whereas when the result in S106 is positive, the process proceeds to S108.

  In S108, it is determined whether or not a third predetermined time (for example, 5 seconds) has elapsed since the affirmative determination in S106 (power failure count). When the result in S108 is negative, the processing of S108 is repeated. When the result is affirmative, the process proceeds to S110 and the bit of the power failure detection ON flag (initial value 0) is set to 1. That is, this flag is set to 1 when a power failure of the commercial power supply 12 is detected (detected), more precisely when it is determined that a power failure has occurred in the commercial power supply 12, while at other times (specifically, Is reset to 0 when no power failure has occurred in the commercial power source 12 (for example, when power recovery of the commercial power source 12 is detected as described later).

  Returning to the description of FIG. 3, when the result in S12 is negative, that is, when the bit of the power failure detection ON flag described above is 0, the process proceeds to S14, and it is determined whether or not a heat request (operation command) has been made by the operator. . S14 determines that a heat request has been made, for example, when hot water is used in the heat load 66 and the temperature of the hot water in the hot water storage tank 60 decreases.

  When the result in S14 is negative, the process returns to S12. When the result is affirmative, the process proceeds to S16, and the engine 22 is started, and the process proceeds to S18 to perform the idle operation in the engine 22. Next, the process proceeds to S20, and in order to block the connection with the commercial power source 12 until the operation of the engine 22 is stabilized, the process waits until a re-linkage blocking time (for example, 2 sec) elapses. Start power generation. As a result, the generated power of the power generation unit 26 is supplied to the electric load 14 in conjunction with the commercial power supply 12, and the hot water of the hot water storage tank unit 58 is supplied to the heat load 66 and the like.

  Next, the process proceeds to S24, and it is determined again whether or not the commercial power supply 12 has a power failure based on the bit of the power failure detection ON flag described above. When the result in S24 is negative, the program proceeds to S26, in which it is determined whether there is still a heat request, and when the result is affirmative, the processing returns to S24.

  On the other hand, when the result in S26 is negative, the program proceeds to S28, where the power generation by the generator 20 is stopped, and the program proceeds to S30, where the operation of the engine 22 is also stopped and the program is terminated.

  When the result is affirmative in S24, that is, when a power failure occurs in the commercial power supply 12, the process proceeds to S32, the power generation in the generator 20 is stopped, and the process proceeds to S34 for a fourth predetermined time (predetermined time). It is determined whether or not a time (for example, 20 sec) has elapsed. When the result is negative in S34, the process returns to S34, while when the result is positive, the process proceeds to S36 and the engine 22 is temporarily stopped.

  Next, the process proceeds to S38, and the DC / DC converter 24b is connected to the battery 23 to start the self-sustained operation, and the boost of the battery output is started. In S40, the engine 22 is cranked by the boosted battery output. Start. Note that if the result in S12 is affirmative, the process proceeds to S38.

  Next, in S42, it is determined whether or not the warm-up operation of the engine 22 has been completed. In S42, for example, it is determined that the warm-up operation has been completed when a preset warm-up operation time has elapsed. When the result in S42 is negative, the process returns to S42. When the result is affirmative, the process proceeds to S44, where the inverter output relay 36 is turned on to start the supply of AC power from the generator 20 to the electric load 14.

  As described above, when starting independent operation, the power generation in the generator 20 is stopped and the engine 22 is also temporarily stopped, and then the engine 22 is restarted and the generated power is output again from the generator 20. This is because it is necessary to reliably disconnect the interconnection with the commercial power source 12, and an excessive load is imposed when an electric load 14 having a power generation capacity (rated output) higher than that of the generator 20 is connected. This is to prevent this.

  Next, in S46, based on the power failure detection ON flag, it is determined whether or not the commercial power source 12 has recovered, that is, whether or not the commercial power source 12 has been restored and the power failure has ended.

  FIG. 5 is a flowchart showing a process for detecting the power recovery. The program in FIG. 5 is executed in parallel with the processing of the flowchart in FIG.

  As shown in FIG. 5, first, in S200, a state in which the voltage between the UN of the commercial power supply 12 and the voltage between VN is equal to or higher than a second predetermined voltage (for example, 108 V) set to a value larger than the first predetermined voltage is the fifth. It is determined whether or not it has continued for a predetermined time (for example, 100 msec) or whether the state where the ATS contact ON signal is output from the ATS 40b continues for a sixth predetermined time (for example, 100 msec).

  When the result in S200 is negative, the process of S200 is repeated. When the result is positive, the process proceeds to S202, and it is determined whether or not a seventh predetermined time (for example, 2 seconds) has elapsed since the result of positive in S200 (recovery count). When the result in S202 is negative, the program returns to S202. When the result is positive, the program proceeds to S204, in which the power failure detection ON flag bit is reset to 0 and the program is terminated.

  Returning to the description of FIG. 3, when the result in S46 is negative, the process of S44 is repeated, while when the result is affirmative, that is, when the power failure detection ON flag bit is 0, the process proceeds to S48. Is stopped, the program proceeds to S50 and the operation of the engine 22 is also stopped and the program is terminated (the autonomous operation is terminated). In addition, after the commercial power source 12 is restored, for example, the processing after S12 is executed, and the interconnection operation with the commercial power source 12 is appropriately executed according to a heat request or the like.

  FIG. 6 is a time chart for explaining a part of the above-described processing, specifically, the operation of the cogeneration apparatus 10 from the power failure of the commercial power supply 12 to the power recovery.

  As shown in FIG. 6, when a heat request is made from the operator at time t1 (S14), the engine 22 is started (S16). At time t2, the inverter output relay 36 is turned on to start supplying power from the generator 20 to the electric load 14.

  When a power failure occurs in the commercial power source 12 at time t3 (for example, when the UV of the commercial power source 12 is below a third predetermined voltage (for example, 192 V) and continues for an eighth predetermined time (for example, 20 msec)), the ATS 40b and the exhaust heat are discharged from the battery 23. Electric power is supplied to the pump 74. Accordingly, the ATS 40b can be operated even during a power failure, and the exhaust heat pump 74 can be driven, so that the coolant temperature of the engine 22 does not rise excessively.

  Further, at time t3, since it is detected that the cogeneration apparatus 10 is operating independently based on the output frequency of the inverter 24c, the inverter output relay 36 is turned off (S100, S102). Since the voltage drop of the commercial power supply 12 is also detected on the ATS 40b side, the ATS contact 40b1 is turned off immediately after the time t3, and the ATS contact off signal is output at the time t4 when the contact 40b1 is turned off and the specified time has elapsed. To do.

  At time t5 when the third predetermined time has elapsed since the output of the ATS contact-off signal, the bit of the power failure detection ON flag is set to 1, that is, the occurrence of power failure of the commercial power supply 12 is determined (S106 to S110). At time t6 when the fourth predetermined time has elapsed since the power failure was detected, the engine 22 is temporarily stopped (S34, S36).

  Next, at time t7, the DC / DC converter 24b is connected to the battery 23 to start boosting the battery output (S38), and the engine 22 is cranked and started with the boosted battery voltage (S40). Note that, after the engine 22 has completely exploded, the above-described pressure increase is stopped.

  At time t9, the driving power source of the exhaust heat pump 74 is switched from the battery 23 to the generator 20. Thereby, it can prevent that the battery 23 is exhausted at the time of a power failure. Next, when the warm-up operation of the engine 22 is completed at time t10, the inverter output relay 36 is turned on, and supply of AC power from the generator 20 to the electric load 14 is started (S42, S44).

  Note that the fuel adjustment map of the engine 22 is switched (changed) during the independent operation. FIG. 7 is a graph showing the fuel adjustment map.

  As shown in FIG. 7, in the power generation unit 26, the fuel supply amount supplied to the engine 22 is also constant (in other words, in other words, in order to make the output voltage constant (rated output) when interconnected with the commercial power supply 12. The operation is controlled such that the throttle opening is also constant). On the other hand, when a power failure occurs in the commercial power supply 12 and the self-sustained operation is performed, the power demand in the electric load 14 is detected based on the current sensor 42, and the detected power demand (the output power on the horizontal axis in FIG. 7 is detected). The fuel supply amount of the engine 22 is adjusted according to (corresponding) (in other words, the throttle opening is adjusted according to the power demand). Specifically, the fuel supply amount (in other words, the throttle opening) of the engine 22 is set to be proportional to the power demand, specifically, to increase as the power demand increases.

  Returning to the description of FIG. 6, when power recovery of the commercial power supply 12 is detected based on the voltage of the commercial power supply 12 and the ATS contact signal at time t <b> 11 (S <b> 200), the inverter output relay 36 is turned off for the seventh predetermined time. At time t12 when lapsed, the bit of the power failure detection ON flag is reset to 0 and the operation of the engine 22 is stopped (S202, S204, S50).

  In the ATS 40b, the ATS contact 40b1 is turned on at a time t13 after a predetermined time (for example, 3 sec) has elapsed since the power recovery was detected at the time t11. Thereafter, at time t14, for example, when the UV of the commercial power source 12 continues for a ninth predetermined time (for example, 10 sec) at or above the fourth predetermined voltage (for example, 216 V), the power of the ATS 40b is switched from the battery 23 to the commercial power source 12.

  As described above, in the embodiment of the present invention, the generator 20 that can be connected to the AC power supply path 16 from the commercial power system (commercial power source) 12 to the electric load 14 and the internal combustion engine that drives the generator. In the cogeneration apparatus 10 including at least the power generation unit 26 including the (engine) 22, a power failure determination means for determining whether or not the commercial power system 12 has failed (ECU 24a of the power generation control unit 24, S100 to S110), When it is determined that the commercial power system 12 has failed, the internal combustion engine 22 is temporarily stopped, and then when a self-sustained operation is started, a booster power source (DC / DC converter) 24b is connected to the battery 23 to connect the internal combustion engine. An internal combustion engine starting means for starting the engine (ECU 24a of the power generation control unit 24; S24, S36 to S40); After, and as configured including the generator 20 from the power supply start means for starting supply of AC power to the electrical load 14 (ECU24a.S44 the power generation control section 24).

  Thereby, when a power failure occurs in the commercial power system 12 and shifts to the independent operation, the operation of the engine 22 can be appropriately controlled with a simple configuration, and thus the independent operation can be reliably started.

  In addition, inverter output abnormality determining means (ECU 24a of the power generation control unit 24, S100) for determining whether or not abnormality has occurred in the output of the inverter 24c based on the output frequency of the inverter 24c connected to the generator 20 is provided. The power failure determination means determines that the commercial power system has failed when the voltage of the commercial power system is equal to or lower than a predetermined value (first predetermined voltage) and an abnormality has occurred in the output of the inverter 24c. Since it is configured to determine whether or not a power failure has occurred based on the voltage of the commercial power system 12 and the output of the inverter (S100, S104, S110), the power failure of the commercial power system 12 is surely generated. And it can be detected accurately.

  Further, the inverter output abnormality determining means is configured to vary the output frequency of the inverter 24c and determine that an abnormality has occurred in the output of the inverter 24c when the fluctuation range of the output frequency is equal to or greater than a predetermined value. (S100), the presence or absence of an abnormality in the output of the inverter 24c can be accurately determined with a simple configuration, whereby a power failure in the commercial power system 12 can be detected more reliably.

  Specifically, when the output of the inverter 24c connected to the generator 20 is connected to the commercial power system 12 and supplied to the electric load 14, even if the output frequency is intentionally slightly changed, The fluctuation range is suppressed to less than the predetermined value because the influence of the power from the commercial power system 12 is large. On the other hand, if the output frequency of the inverter 24c is changed when the commercial power system 12 has a power failure, the fluctuation range becomes equal to or greater than a predetermined value because the commercial power system 12 is not affected by the power. By using this, it is possible to accurately determine whether or not an abnormality has occurred in the output of the inverter 24c with a simple configuration, and based on that, determine whether or not a power failure has occurred in the commercial power system 12. Therefore, it is possible to detect a power outage more reliably.

  The internal combustion engine starting means is configured to temporarily stop the internal combustion engine 22 when a predetermined time has elapsed since it was determined that the commercial power system 12 was out of power (S34, S36). Can be controlled more appropriately in accordance with the state of the commercial power system 12, and thus the autonomous operation can be started more reliably.

  The power supply start means is configured to start supplying AC power from the generator 20 to the electric load 14 after the internal combustion engine 22 is started and the warm-up operation is completed (S42, S44), a stable output can be supplied to the electric load 14 from the generator 20 driven by the engine 22.

  In the above description, the engine 22 is a gas engine using city gas / LP gas as fuel, but it may be an engine using gasoline fuel or the like. Moreover, although each predetermined voltage, each predetermined time, the rated output of the power generation unit 26, the displacement of the engine 22 and the like are shown as specific values, these are examples and are not limited.

  The AC power output from the commercial power supply 12 is 100 / 200V. However, when the AC power output from the commercial power supply 12 exceeds 100 / 200V, the corresponding voltage is output from the power generation unit 26. Nor.

  DESCRIPTION OF SYMBOLS 10 Cogeneration apparatus, 12 Commercial power supply (commercial power system), 14 Electric load, 16 Feeding path, 20 Generator, 22 Engine (internal combustion engine), 23 Battery, 24 Power generation control part, 24a ECU (electronic control unit), 24b DC / DC converter (step-up power supply), 24c inverter, 26 power generation unit

Claims (5)

  Whether the commercial power system has a power failure in a cogeneration system comprising at least a power generation unit comprising a generator connectable to an AC power supply path from the commercial power system to an electrical load and an internal combustion engine that drives the generator A power failure determination means for determining whether or not the commercial power system has been out of power, and when the internal combustion engine is temporarily stopped and then a self-sustaining operation is started, a boosting power source is connected to a battery to A cogeneration apparatus comprising: an internal combustion engine starting means for starting the power supply; and a power supply starting means for starting supply of AC power from the generator to the electric load after the internal combustion engine is started.   Inverter output abnormality determination means for determining whether abnormality has occurred in the output of the inverter based on the output frequency of the inverter connected to the generator, and the power failure determination means has a predetermined voltage of the commercial power system 2. The cogeneration apparatus according to claim 1, wherein when it is determined that an abnormality has occurred in the output of the inverter that is equal to or less than the value, the commercial power system is determined to have failed.   3. The inverter output abnormality determining means varies the output frequency of the inverter and determines that an abnormality has occurred in the output of the inverter when the fluctuation range of the output frequency is a predetermined value or more. The described cogeneration system.   The cogeneration system according to any one of claims 1 to 3, wherein the internal combustion engine starting means temporarily stops the internal combustion engine when a predetermined time elapses after it is determined that the commercial power system has failed. apparatus.   5. The power supply start unit starts supply of AC power from the generator to the electric load after the internal combustion engine is started and warm-up operation is completed. 6. A cogeneration apparatus according to crab.

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